How can we encourage people to review first posts, late answers, close votes, etc.? I am asking because my suggested reviews still are not reviewed.
I agree with you: reviewing is important and we should be encouraging other users to do it. Here are 2 methods I frequently use to get other users to review:
Frequently post on meta about reviews you want to discuss. This could include reviews you think were completed incorrectly, reviews you aren't sure how to complete, etc. Users who come across them on Meta could become interested in your question, and possibly reviewing in general.
Set an example and complete some reviews yourself. Sometimes people end up doing things because other people did. Review and it'll probably encourage others to do so as well. Note: this method requires 350 reputation.